Dual layer switch photoreceptor structures for digital imaging

Abstract

An electrophotographic imaging member including a charge generating layer and a heterogeneous charge transport layer, the charge transport layer having regions of charge transport and inactive regions and the charge transporting regions are in contact with each other. This imaging member has characteristics that enable high quality and high contrast imaging.

What is claimed is: 
     
       1. An electrophotographic imaging member comprising a conductive substrate;   a charge generating layer; and   a charge transport layer; said charge transport layer comprising   at least two charge transporting regions and   an electrically inactive region, said charge transporting regions in contact with each other forming a convoluted charge transport path.   
     
     
       2. An electrophotographic imaging member according to claim 1 wherein the charge transporting regions consists of particles of inorganic photoconducting materials. 
     
     
       3. An electrophotographic imaging member according to claim 1 wherein the charge transporting regions consists of microcrystalline particles of organic pigments. 
     
     
       4. An electrophotographic imaging member according to claim 1 wherein the charge transporting regions consists of microcrystalline particles of organic charge transporting material. 
     
     
       5. An electrophotographic imaging member according to claim 1 wherein the charge transporting regions consists of regions of organic charge transporting material. 
     
     
       6. An electrophotographic imaging member according to claim 5 wherein the charge transport layer is fabricated from an organic block copolymer consisting of charge transporting blocks that are separated by electrically inactive blocks. 
     
     
       7. An electrophotographic imaging member according to claim 6 in which the charge transporting blocks form regions of charge transport which are in contact with each other. 
     
     
       8. An electrophotographic imaging member according to claim 1 wherein the charge transporting regions have linear dimensions of between 0.0015 micrometers to 5 micrometers. 
     
     
       9. An electrophotographic imaging member according to claim 2 wherein the inorganic charge transporting particles are zinc oxide crystallites. 
     
     
       10. An electrophotographic imaging member according to claim 2 wherein the inorganic charge transporting particles are cadmium sulphide crystallites. 
     
     
       11. An electrophotographic imaging member according to claim 3 wherein the organic charge transporting particles are phthalocyanine pigment crystallites. 
     
     
       12. An electrophotographic imaging member according to claim 3 wherein the organic charge transporting particles are perylene-based pigment crystallites. 
     
     
       13. An electrophotographic imaging member according to claim 3 wherein the organic charge transporting particles are perinone-based pigment crystallites. 
     
     
       14. An electrophotographic imaging member according to claim 4 wherein the organic charge transporting particles are crystallites of aryl amine, electron donor molecules. 
     
     
       15. An electrophotographic imaging member according to claim 4 wherein the organic charge transporting particles are crystallites of electron transport molecules. 
     
     
       16. An electrophotographic imaging member according to claim 6 wherein the charge transporting block of the organic charge transporting block copolymer is selected from the group consisting of Poly N vinyl carbazole, polyaryl amines and polysilylenes. 
     
     
       17. An electrophotographic imaging member according to claim 6 wherein the electrically inactive block of the organic charge transporting block copolymer is selected from the group consisting poly methyl methacrylates, polycarbonates and polystyrene. 
     
     
       18. An electrophotographic imaging member according to claim 1 wherein the charge generation layer is interposed between the substrate and the charge transport layer. 
     
     
       19. An electrophotographic imaging member according to claim 1 wherein the charge transport layer is interposed between the substrate and the charge generation layer. 
     
     
       20. An electrophotographic imaging member according to claim 1 wherein said charge generator layer has a thickness of between about 0.05 micrometer and about 5 micrometers. 
     
     
       21. An electrophotographic imaging member according to claim 1 wherein said charge transport layer has a thickness of between about 5 micrometers and about 50 micrometers. 
     
     
       22. An electrophotographic imaging member according to claim 1 wherein the charge generating pigment in the charge generating layer is dispersed in a resinous binder in an amount of between about 5 percent by weight and about 95 percent by weight based on the total weight of said charge generating layer. 
     
     
       23. An electrophotographic imaging member according to claim 1 wherein the charge layer is vacuum deposited. 
     
     
       24. An electrophotographic imaging member according to claim 1 wherein the substrate is comprised of a drum. 
     
     
       25. An electrophotographic imaging member according to claim 1 wherein the substrate is a flexible belt. 
     
     
       26. An electrophotographic imaging member according to claim 1 wherein the substrate is a flexible belt with a transparent conductive coating and the said supporting substrate is transparent. 
     
     
       27. An imaging process comprising providing an electrophotographic imaging member comprising a charge generating layer and a charge transport layer, said charge transport layer comprising charge transporting regions and electrically inactive regions, said charge transporting regions in contact with each other, depositing a uniform electrostatic charge on said imaging member with a corona charging device, exposing said imaging member to a light image pattern to form an electrostatic latent image on said imaging member, developing said electrostatic latent image with electrostatically attractable marking particles to form a visible toner image, transferring said toner image to a receiving member and repeating said depositing, exposing, developing and transferring steps. 
     
     
       28. A charge transport material for use in an electrophotographic imaging system comprising: a plurality of charge transporting regions; and   an electrically inactive region, said charge transporting regions comprising a convoluted charge transport path.